Coil component

Abstract

In a coil component, a second magnetic portion disposed in the vicinity of a coil is designed to have a higher proportion of Fe than a metal magnetic powder-containing resin constituting a first magnetic portion. Therefore, a magnetic flux of the coil flows smoothly. Although the second magnetic portion has a relatively lower withstand voltage than the first magnetic portion, since the second magnetic portion is surrounded by the first magnetic portion, it is not exposed on an outer surface of a magnetic body. For this reason, a situation in which the coil and external terminal electrodes are short-circuited with the second magnetic portion therebetween is effectively curbed, and short-circuiting between the coil and the external terminal electrodes can be curbed.

What is claimed is: 
     
       1. A coil component comprising:
 an insulation substrate provided with a penetration hole; 
 a coil having a first coil portion subjected to insulation coating with a first flat coil pattern formed around the penetration hole on one surface of the insulation substrate; 
 a magnetic body integrally covering the insulation substrate and the coil; and 
 a pair of external terminal electrodes provided on an outer surface of the magnetic body and being respectively connected to end portions of the coil, 
 wherein the magnetic body has
 a first magnetic portion constituted of a metal magnetic powder-containing resin containing metal magnetic powders including Fe and constitutes the outer surface of the magnetic body, and 
 a second magnetic portion surrounded by the first magnetic portion, the second magnetic portion covering at least a part of the coil, and having a higher compositional proportion of Fe than the metal magnetic powder-containing resin constituting the first magnetic portion. 
 
 
     
     
       2. The coil component according to  claim 1 ,
 wherein the coil has a second coil portion subjected to insulation coating with a second flat coil pattern formed around the penetration hole on the other surface of the insulation substrate. 
 
     
     
       3. The coil component according to  claim 1 ,
 wherein the second magnetic portion is present in the whole region of an inward region of the coil. 
 
     
     
       4. The coil component according to  claim 1 ,
 wherein a smallest thickness in a thickness of the first magnetic portion, the smallest thickness is a distance from the outer surface of the magnetic body to the second magnetic portion, is longer than a length of a largest particle of the metal magnetic powders included in the metal magnetic powder-containing resin constituting the first magnetic portion. 
 
     
     
       5. The coil component according to  claim 1 ,
 wherein the magnetic body has a pair of main surfaces facing each other in a thickness direction of the insulation substrate and a pair of end surfaces facing each other in a direction orthogonal to the thickness direction of the insulation substrate, and provided with the pair of external terminal electrodes respectively, and 
 wherein a main surface-side thickness of the first magnetic portion which is a distance from the main surface of the magnetic body to the second magnetic portion is shorter than an end surface-side thickness of the first magnetic portion which is a distance from the end surface of the magnetic body to the second magnetic portion. 
 
     
     
       6. The coil component according to  claim 1 ,
 wherein the second magnetic portion is constituted of a metal magnetic powder-containing resin containing metal magnetic powders including Fe.